1. Field of the Invention
The invention relates to suspension systems and, more particularly, relates to a modular control system designed for the vehicle aftermarket that allows wired or wireless communication with multiple electronically controlled services, including air suspensions, adjustable dampers, engine controllers and the like.
2. Background Art
The invention for which an example embodiment is described herein relates to modular control systems associated particularly with various types of vehicles. For purposes of description, the example embodiment of the modular control system in accordance with the invention will be described with respect to air suspension systems. Accordingly, the following paragraphs will generally describe one type of suspension system, primarily as background. This system is one which is often characterized as an “air-over” suspension system.
Various types of shock absorbers and other suspension devices are known in the vehicle industries. These devices are typically utilized so as to dampen the effects of projections (i.e. bumps) or apertures (i.e. potholes) on roadways for “smoothing” the ride for automobiles, trucks and the like. That is, the shock absorbers comprise mechanical devices designed to smooth out or dampen sudden shock impulses and dissipate kinetic energy. Suspension systems are also used on numerous other types of vehicles, including trains. These suspension systems have been the subject of a substantial amount of development during the past few decades.
For example, one type of suspension system well known in vehicle industries is often referred to as a “coil-over” shock absorber systems. These suspension systems typically employ a fluid-type shock absorber with a cylinder and a piston rod telescopically extending through one end of the cylinder. A coil spring has one end seated the cylinder, while the piston rod extends through the coil spring on a central axis thereof. The other end of the coil spring is seated or otherwise mounted to a vehicle frame or the like, with the far end of the piston rod also appropriately connected to vehicle suspension or frame components.
Although coil-over shock absorber systems are part of the vehicles original manufacture, it is often desired to modify vehicles so as to provide for air-over shock absorber systems. In place of the typical coil springs associated with OEM shock absorber systems, the air-over shock absorber systems utilize various types of air springs in combination with shock absorbers utilizing piston rod and cylinder configurations. In this regard, it is advantageous to provide vehicle owners with conversion assemblies, which include components required to convert coil-over to air-over suspension systems.
General concepts associated with suspension systems and conversions of the same are relatively well known in the arts. For example, Hellyer, et al., U.S. Pat. No. 5,180,144, issued Jan. 19, 1993 describes concepts associated with an air spring module constructed so as to be removably mounted between a damper and a vehicle body. This patent describes the concept that it has been known to employ automotive suspension struts in suspension systems constructed with either coil springs or air springs mounted coaxially about the strut. Problems can be encountered with front suspension struts mounted to the front steerable wheels. When the wheels are steered, the springs can undergo a twisting motion, as the strut body rotates with the wheel. The twisting will undesirably change the characteristics of the coil spring. To solve the problem of torsional twist of the coil springs, a bearing assembly can be placed between the vehicle body and a mounted piston rod of the strut, so as to allow the strut to rotate relative to the body. When incorporating an air suspension system on a strut assembly, such as a MacPherson strut assembly, it is desirable to allow for replacement of the strut without removal or disassembly of the air spring. For this to occur, the air spring needs to be detachable with respect to the strut body and the vehicle body. The Hellyer, et al. patent specifically discloses an air spring module removably mounted on a damper. The damper includes an outer reservoir tube closed at its upper end by a seal cover. A neck of the seal cover receives a reciprocal piston rod extending from the damper. The lower end of the damper is mounted to a wheel assembly in a conventional manner. The module includes a contact piston. The reservoir tube is received within a large diameter portion of the piston, and the piston rod fits in a small diameter portion of the piston.
An elastomeric air sleeve is attached to the outer circumference of the contact piston by a clamp or retainer. A rolling lobe is formed in the portion of the sleeve which travels along the contact piston. The upper portion of the sleeve is secured to a canister by a retainer. The canister is welded to a lower bearing retainer. An isolated bearing assembly is provided between the lower bearing retainer and an upper bearing retainer. An elastomeric mount having a cylindrical sleeve is fitted over a stepped portion of the piston rod. A metallic ring is provided about the mount, and is welded to the lower bearing retainer so as to secure the mount. A lower rate washer is secured to the sleeve at a lower surface of the mount. A plate is connected to the lower bearing container by a retainer ring received in a groove at the outer circumference of a neck portion of the lower bearing retainer. The plate can include a series of downwardly projecting preloaded rubber pads. The pads rest on a series of thrust washers. The thrust washers are mounted about the neck of the lower bearing retainer and held in place by a support secured to the bearing retainer.
With an air spring module having the structure described in the foregoing paragraphs, the module can be mounted to a number of different types of dampers, including hydraulic and pneumatic dampers. For purposes of assembling the module in a vehicle, the contact piston is fitted over the piston rod and the reservoir tube. O-ring seals are provided in a first groove within the neck of the seal cover, so as to provide a seal between the sleeve and the neck. A retainer ring is mounted in a second groove of the neck and is initially compressed as the sleeve is slid over the neck. A complimentary groove is provided in an inner surface of the sleeve, so that the retainer ring springs outwardly and fits snuggly into the groove when the contact piston is in its proper position. With this construction, a relatively quick and removable connection between the lower end of the module and the damper is provided.
Oishi, U.S. Pat. No. 6,332,602 issued Dec. 25, 2001 describes a vehicle suspension system having an annular air chamber. More specifically, Oishi describes the construction of an annular bellows unit for replacing a vehicle suspension coil spring. The coil spring encloses a shock absorber or “hydraulic actuator.” Oishi describes what he considers to be problems associated with known suspension conversion arrangements, where pressurized bellows are substituted for coils. Oishi explains that the pressurized bellows of known systems are incompatible with the concentric mounting of shock absorbers. It is described that shock absorbers are known whereby they are configured for receiving pressurized air for selectively increased ride height, with the pressurized air augmenting conventional springs.
Further described are concepts associated with the use of hydraulic actuators, which are substituted for conventional shock absorbers. The actuators, also being operable for modifying ride height, may use (for example, in “low-rider” applications) a downwardly extending piston rod of a hydraulic actuator connected to a lower suspension A-arm in place of a conventional shock absorber. An oppositely extending cylinder body is connected through a cut-down portion of the original coil spring to the vehicle chassis. An electrically driven pump can feed the single-acting actuator, so as to change the ride height in response to operator input. Oishi states that a disadvantage associated with low-rider actuators known in the prior art is that they produce a particularly harsh ride, with substantially no spring action, because only about half of the original spring is utilized.
Oishi alleges that the vehicle suspension embodiment described in his patent meets the need for an adjustable vehicle suspension biasing element, compatible with concentric shock absorber mountings and otherwise overcoming other disadvantages of the prior art. More specifically, Oishi discloses what he characterizes as an after-market vehicle suspension biasing element. Specifically, an annular bellows apparatus for a vehicle suspension includes an outer bellows, inner bellows, upper flange member and lower flange member. Opposite ends of the outer bellows are sealed through clamping onto outer extremities of the upper and lower flange members by outer clamp rings. The outer bellows also includes generally cylindrical outer extensions formed at opposing ends for receiving the clamp rings.
In addition, the upper and lower flange members have their outer beads reinforced by outer bead rings, and an additional outer bend reinforcing ring. This reinforcing ring is located between adjacent ones of the outer bellows. The reinforcing rings serve so as to prevent outward expansion of bellows segments when the bellows apparatus is pressurized. The outer bellows described by Oishi is a known component utilized in air suspension devices manufactured by Goodyear Tire & Rubber Company.
Oishi further discloses an inner bellows having a generally smaller diameter than the outer bellows. The inner bellows is characterized as being configured so as to withstand outside air pressure, in contrast with the outer bellows which is configured to withstand inside air pressure. The inner bellows includes a series of segments, with inner extensions being formed at opposing ends so as to receive respective inner clamp rings. In this manner, the inner bellows is clamped to the upper and lower flange members of the suspension system.
With the inner and outer bellows, a sealed annular chamber is formed therebetween. Oishi describes that this annular chamber is formed while continuing to preserve the annular configuration of the entirety of the bellows apparatus. A fill port is provided in the lower flange member for purposes of pressurizing the chamber. Oishi describes the concept that the bellows apparatus can be combined with a generally concentric shock absorber, with the bellows apparatus and the shock absorber remaining concentric both when the apparatus is in an extended condition and a compressed condition.
The segments of the inner bellows are described as tapering inwardly at opposing ends, with oppositely facing elements integrally formed and joined at the outer peripheral extremities thereof. The inner bellow segments can be reinforced by outside reinforcing rings, encapsulated or otherwise connected so as to prevent contraction of outer peripheral extremities of the inner bellow segments.
Oishi also describes two alternative embodiments for the bellows apparatus, both consisting of alternative configurations for the inner bellows. In one embodiment, the inner bellows includes a series of inside reinforcing rings located and connected at inner peripheral extremities of adjacent inner bellow segments. This embodiment of the inner bellows includes an outwardly projecting bead flange joined to a counterpart of the inner extension. A counterpart of the inner bead ring is encapsulated within the bead flange. In another embodiment, an axially split counterpart of the upper flange member includes both an outer flange and an inner flange, with the flanges clamped on opposing sides of the bead flange by a series of clamp fasteners. A counterpart of the outer bellows is connected to the upper flange, which is formed with a shallow counterpart of a groove depression, so as to have the outer extension of the outer bellows clamped thereto. The extension is formed without the outer bead ring and outer reinforcing ring that is included in other bellows.
In summary, Oishi considers his patent to disclose a bellows apparatus for replacing a coil spring in a vehicle suspension having a shock absorber mounted generally concentrically with the previous location of the spring. Also, the bellows apparatus described in Oishi allegedly can be used with a low-rider hydraulic actuator, replacing an original spring that would otherwise have to be shortened. An appropriate ring member couples the bottom of the bellows apparatus to a cylinder body of the actuator, with the ring member resting on a shoulder that is formed by a lower enlargement of the cylinder body.
Okamoto, U.S. Pat. No. 6,398,198 issued Jun. 4, 2002 is directed to a bellows-type air spring with a vehicle height adjustable suspension arrangement utilizing the air spring. More specifically, a particular embodiment of a bellows-type air spring is utilized with specific structures of upper and lower mounting units, and with two additional alternative embodiments of the upper mounting units. In one embodiment, the height adjustable suspension includes an upper mounting unit mounted to a chassis of the vehicle, with a shock absorber mounted to the upper unit and a bellows body to the shock absorber.
The bellows body is characterized as a two-stage air spring, with a hollowed cylindrical shape and first and second open ends. First and second end members, each having a plate-like shape, are provided in the first and second open ends of the bellows body. The body defines diametrically large portions which are vertically aligned along a longitudinal axis thereof, and diametrically smaller portions located at the upper and lower open ends of the bellows body, and also between diametrically larger portions. Peripheral edges of the upper and lower open ends are outwardly bent so as to form engaging portions, with wire rings mounted therein. Also, a ring is mounted within one of the diametrically smaller portions positioned between the larger portions, so as to prevent the smaller portion from expanding radially outward.
First and second end members have peripheral edges bent radially inward, so as to form engaging portions which respectively engage with additional engaging portions, allowing the first and second end members to seal the upper and lower open ends of the bellows body. The first end member includes a central portion defining a through hole, with four inwardly threaded portions having their axes extending parallel to the longitudinal axis of the bellows body and arranged along a concentric circle of the through hole. An air valve mounting portion is arranged concentric of the through hole, so as to introduce and discharge air into and from the bellows body, respectively.
The second end member has a central portion defining a further through hole with a diameter smaller than the first through hole of the first end member. The second end member is provided with a pair of outwardly threaded portions having their axes extending parallel to the longitudinal axis of the bellows body. The outwardly threaded portions are oppositely positioned with the through hold therebetween. The shock absorber is conventional in nature, and includes a body extending through the through hole of the first end member. The retractable rod of the shock absorber extends through the through hole of the second end member. The body of the shock absorber is received by a spring receiving member disposed under the first member. The spring receiving member includes a hollowed cylindrical portion for receiving the body, and a flange portion integrally formed with a base portion of the hollowed cylindrical portion. The cylindrical portion of the spring receiving member includes a lower end portion secured to the shock absorber body by welds. The flange portion of the spring receiving member defines concave portions, for receiving bolts adapted to be threadably engaged with inwardly threaded portions of the first end member. O-rings are provided around the bolts within the concave portions, for prevention of air leakage from the bellows body. The flange portion of the spring receiving member includes an upper surface facing the first end member, defining an annular concave portion for receiving another O-ring, surrounding the respective inwardly threaded portions.
The flange portion of the spring receiving member also defines an annular inclined surface, so as to form a reservoir for receiving liquid silicone to prevent air leakage from the bellows body. The bellows body is thus subjected to an air leak prevention measurement through not only the O-rings, but also the liquid silicone.
Turning to the upper portion of the shock absorber, the retractable rod extends through a dish-like adapter, and above the upper end of the second end member. The adapter includes a plate-like bottom wall, with an annular side wall integrally formed with a peripheral edge of the bottom wall. The bottom wall has a central portion defining a through hole for receiving the retractable rod, and an annular, concave portion in communication with a lower portion of the through hole for receiving an O-ring surrounding the retractable rod. In this manner, the bellows body is subjected to a secured air leakage prevention measurement by means of the O-ring resting on the annular concave portion. The bottom wall of the adapter defines through holes for receiving outwardly threaded portions, which are threadably engaged with nuts, thus securing the adapter to the second end member. The side wall includes a circumferential periphery, defining therein an annular concave portion.
The upper mount unit includes what Okamoto characterizes as a “holding means” comprising an annular member made of metal for receiving an outwardly threaded portion formed on the upper end of the shock absorber rod. Also included is a rod holding member with an annular damper rubber provided around the annular member. An annular fixing plate is secured to the circumferential periphery of the rod holding member, and a dish-like receiving plate secured to the circumferential periphery of the rod holding member below the annular fixing plate.
The fixing plate is provided with stud bolts, extending through through holes of the chassis of the vehicle. The stud bolts are threadably engaged with nuts, thus mounting the upper mount unit to the chassis. The outwardly threaded portion of the retractable rod extends through a washer and the annular member of the upper mount unit. This threaded portion has a portion protruding from the second end member, to which a nut is threadably engaged, thus mounting the shock absorber to the upper mount unit. Between the annular concave portion and the receiving plate is a bearing, which allows the adapter to be rotatably supported on the upper mount unit.
With respect to assembly, the spring receiving members first welded onto the body of the shock absorber. The liquid silicone is then poured into the reservoir defined by the annular inclined surface. The first end member positioned on the lower upper end of the bellows body is then mounted to the spring receiving member by allowing the shock absorber body to extend through the through hole of the first end member. Bolts are threadably engaged with the inwardly threaded portions of the first end member through the concave portions. The tightening force of the bolts will squeeze the O-ring pair, thereby achieving a hermetic sealing of the lower open end of the bellows body.
The second end member positioned in the upper open end of the bellows body is then mounted to the adapter by allowing the outwardly threaded portions to extend through the through holes of the adapter. Nuts are threadably engaged with the outwardly threaded portions. The tightening force of these nuts will squeeze the O-ring associated with the second end member, thereby achieving a hermetic sealing of the upper open end of the bellows body.
The outwardly threaded portion of the retractable rod of the shock absorber will extend through the annular member of the upper mount unit, and is engaged with a nut. The upper mount unit is thus mounted to the shock absorber. When the assembled suspension is mounted to the chassis, stud bolts are inserted into through holes within the chassis, and are tightened with nuts. In some instances, the upper mount unit may be pre-mounted to the chassis. In this case, the upper mount unit is omitted from the vehicle height adjustable suspension assembly. The retractable rod of the shock absorber then has the outwardly threaded portion of the same extending through the annular member of the rod holding member, and is threadably engaged with the nuts. Okamoto further discloses the concept that an air feeding system for feeding (and discharging) air into the bellows body may include an air tank, compressor and switching apparatus controllable by a driver in the driver compartment. Okamoto also discloses alternative embodiments associated with the configuration of the upper mount unit.
Morrow, U.S. Pat. No. 6,382,602 issued May 7, 2002, is directed to a method for retrofitting height and load adjustable air springs to coil spring-based Mac Pherson strut assemblies. The method includes removal of the coil spring and removing material from an outer surface of a bump stop seat, so that the outside diameter of the stop seat is slightly less than the outer diameter of the strut housing. This allows a lower air spring mount to readily slide down the strut housing during retrofitting. The lower spring seat is then removed from the strut housing, and the lower air spring mount is slide down the strut housing. The mount includes pre-installed O-rings in machined grooves within the lower air spring mount. The mount is seated on an existing weld, with the weld being previously used to attach the original coil spring seat to the strut housing.
The lower air spring mount is then rotated and correctly positioned about the strut housing, so that an air fitting bore is located perpendicular to a lower hub mounting clevis, and located free of obstructions. A fillate of silicone is then applied around the upper location where the strut housing passes through the lower air spring mount. The fillate acts in conjunction with the O-rings so as to seal the lower spring air spring mount to the strut housing in an air tight configuration.
An air spring is then positioned around the strut piston rod and the strut housing. The air spring includes one chamber having a flexible rubber membrane arranged in single, double or triple bellows orientation. The air spring includes upper and lower portions. A lower bead ceiling ring is provided between the lower portion of the air spring and a top portion of the lower air spring mount. The lower portion of the air spring is then secured to the lower air spring mount through the use of Allen head cap screws and nuts. An upper air spring mount is then slid down the strut piston rod, until the mount rests on the top of the upper portion of the air spring. The upper air spring mount includes pre-installed O-rings and machined grooves therein. The O-rings are used to seal the upper air spring mount to the strut piston rod in an air tight fashion.
An upper spring bead ceiling ring is provided between the upper portion of the air spring and a bottom portion of the upper air spring mount. The upper portion of the air spring is secured to the upper air spring mount through the use of Allen cap screws and nuts, so as to ensure an air tight seal between the upper portion of the air spring and the upper air spring mount. In this manner, a retrofit arrangement is provided.
Voelkel, U.S. Pat. No. 6,581,918 issued Jun. 24, 2003, discloses a shock absorber having a hollow spring with a chamber comprising a proximal end, a distal end and a bellows composed of a springy material connecting the two ends and enclosing the chamber. A shock absorber cylinder extends through and is attached to the hollow spring proximal end, with the piston extending through and slidably engaging the hollow spring distal end. The piston is characterized as having a “contacting” device located distally of the hollow spring distal end for urging the distal end proximally when the contacting device is forced against the hollow spring distal end. The device urges the piston distally when the hollow spring distal end is forced against the contacting device. Voelkel also discloses the concept of powered control of application and discharge of air to and from the air spring chamber.
LaPlante, et al, U.S. Pat. No. 6,904,344, issued Jun. 7, 2005, is directed to semi-active control methodology for a shock absorber control system. The system is disclosed as being adapted for a coil spring and real-time adjustable shock absorber system. LaPlante et al discloses methodology directed to processing so as to account for non-inertial spring/mass system responses, and multi-dimensional forces acting upon the system. The methodology also includes processing in the form of an acceleration hedge calculation, so as to accurately define system operation at travel extremes. In summary, the methodology is directed to concepts associated with producing a series of valve control signals, selecting among these control signals, and applying a selected control signal to an appropriate valve in a closed-loop feedback system. In this manner, energy is adjusted within the spring/mass system.
In one embodiment, LaPlante et al discloses the spring/mass system as comprising at least two masses, with a spring coupled between the masses and with a controllable damper. The purpose of the shock absorber controller is to generate a target control signal, so as to adjust the energy in the spring/mass system. A series of input circuits is configured so as to receive input signals representing parameters selected from a group consisting of a relative position of the masses, relative mass velocities, mass accelerations, a spring constant for the spring/mass system, a mass of at least one of the masses, a critically damped coefficient of the spring/mass system, and an upper force threshold for a critically damped force in the spring/mass system. An “endstop” position for the spring/mass system is also determined. Processing configurations are utilized so as to determine if the spring/mass system is compressing or expanding, based on at least the relative velocity of the masses with respect to one another. Second and third processors are configured so as to generate control signals to control the damper in response to at least one of the input signals. A fourth processor is configured so as to select one of the control signals based on the spring/mass system compressing or expanding, and based on a comparison of the control signals. The fourth processor configured to generate the target control signal based on the selected signal, with the target signal being proportional to a desired energy in the spring/mass system.
A relatively early but substantial advance in the vehicle suspension system arts is represented by Pemberton, U.S. Pat. No. 3,727,899, issued Apr. 17, 1973. Pemberton discloses a spring suspension unit adapted to extend between a vehicle frame and suspension members. The unit includes a coil spring extending between the members, with an inflatable elastomeric bag disposed within the coil spring. The bag is expandable so as to dispose side wall portions of the bag between the convolutions of the spring. The bag is disclosed as being formed of cup-shaped portions, having end and side walls. The cup-shaped portions also have radially outwardly projecting flanges at their open ends. The flanges are heat-sealed in an abutting air-sealed relationship, and provide a radially projecting convolution engaging ring. Means are also provided which lead from the bag's exterior and to one of the portions of the bag, so as to introduce pressurized air.
Turning to the more specific issues related to the present invention, air suspension systems have seen rapid growth in OEM and aftermarket industries. High volume OEM applications are engineered to fit a particular vehicle application, with minimal variations. Low-volume aftermarket systems must be more flexible, so as to allow multi-vehicle fitment and multiple system variations. Traditionally, each variation is engineered separately, with engineered components specific to each variation. However, if air suspension system variations with key components could be constructed so as to be used flexibly, a modular system could be proposed. Common key components would reduce system variation engineering time, and provide for greater volumes per year, while reducing component and system costs.
With respect to the foregoing, the vehicle industries have certain types of unique needs. For control systems for controlling of various types of vehicle systems, customers desire a simple and relatively small interface. Customers also desire a simple installation, with expansion capabilities as the customers invest additional monies into their vehicles. Correspondingly, suppliers wish to use common components for multiple systems, so as to keep costs reduced, but still offer a number of product variations. Also, suppliers wish to offer expansion capabilities, so as to sell additional product.